Lung adenocarcinoma back pain is a common symptom when lung cancer develops to a certain stage, especially in middle or late stage. Back pain caused by lung adenocarcinoma is a paroxysmal stabbing or cramping pain, which can be aggravated when breathing, coughing or physical activities. There are two main reasons for its occurrence: First, the lung adenocarcinoma mass grows very big and directly stimulates the neighboring pleura causing pain, which is obviously aggravated when breathing, coughing and other pleural activities. Second, distant metastasis will occur when lung adenocarcinoma reaches the late stage, if bone metastasis occurs, especially the common rib and thoracic vertebrae metastasis in the back, it can lead to severe back pain, which is closely related to the physical activities, and its degree of severity is bigger than that of the pain generated by the cancerous tumor stimulating the pleura. Of course, there is a relatively rare cause that lung adenocarcinoma mass obstructs the airway leading to obstructive pneumonia, and the inflammation stimulates the pleura or lung tissues in the back leading to pain, which is not very intense, usually dull pain, but it will be aggravated when coughing or breathing.